A Multicenter Randomized Three-Arm Phase II Study of (1) Everolimus, (2) Estrogen Deprivation Therapy (EDT) with Leuprolide plus Letrozole, and (3) Everolimus plus EDT in Patients with Unresectable Fibrolamellar Carcinoma

Background. Fibrolamellar carcinoma (FLC) is an uncommon malignancy in young people and is sometimes associated with pregnancy and oral contraceptive use. Immunohistochemical staining and genetic profiling of FLC tumor specimens have revealed aromatase overexpression. The overexpression of mTOR and S6 kinase has been noted in 25% of FLC. On the basis of interaction between estrogen and the PI3K/Akt/mTOR pathway, we hypothesized that suppression of estrogen and mTOR signaling could have antineoplastic activity in FLC. Methods. Patients were randomized to arm A (everolimus), arm B (letrozole/leuprolide; estrogen deprivation therapy [EDT]), or arm C (everolimus/letrozole/leuprolide). Upon disease progression, patients in arm A or B could proceed to part 2 (everolimus/letrozole/leuprolide). The primary endpoint was progression-free survival (PFS) at 6 months (PFS6) assessed using a Simon's minimax two-stage design, hypothesizing an improvement in PFS6 from 40% to 64% with the study regimen. Results. Twenty-eight patients were enrolled. An unplanned analysis was performed because of perceived concern for lack of efficacy. Stable disease was observed in 9 of 26 evaluable patients (35%). PFS6 was 0%. Median overall survival (OS) was 12.4 months (95% confidence interval [CI], 7.4-20.9) for the whole study cohort. Grade 3 adverse events in >= 10% of patients were nausea (11%), vomiting (11%), anemia (11%), elevated aspartate transaminase (AST; 32%), alanine transaminase (ALT; 36%), and alkaline phosphatase (14%). All 28 patients experienced an event for PFS outcome, and four deaths were due to disease progression. Conclusion. Neither EDT nor mTOR inhibition improved outcomes in FLC. Other treatment strategies are needed.